1. Field of the Invention
The present invention relates to a start control device for controlling start of, for example, an engine of a vehicle.
2. Description of the Related Art
Up to now, for the purpose of improving fuel efficiency of an automobile and reducing environmental loads, an automatic engine stop and restart system has been developed. In the automatic engine stop and restart system, when a given condition for stopping the engine is satisfied by an operation of a driver, for example, when an ON-operation of a brake is conducted at or below a given vehicle velocity, fuel supply is automatically cut, and the engine is automatically stopped. Meanwhile, when a given condition for restarting the engine is satisfied by the operation of the driver, for example, when a brake release operation is conducted or when an accelerator press-down operation is conducted, fuel injection is restarted, and the engine is automatically restarted.
In the automatic engine stop and restart system as described above, as disclosed in Japanese Patent No. 4214401, a starter capable of controlling the pushing operation of a pinion and the driving of a motor (rotation of the pinion) independently from each other, has been developed so that the engine may be restarted even during the engine rotation down period immediately after an automatic stop of the engine. In such a starter, in order to change a travel speed of the pinion to reduce a start time, a duty control is conducted, to thereby adjust a current flowing in a pinion driving coil, so that the pushing force of the pinion may be controlled.
Further, as disclosed in Japanese Patent Application Laid-open No. 2002-122059, a pull-in coil and a hold coil are disposed in a plunger that conducts the pushing operation of the pinion, and when the motor starts to be driven, the energization of the pull-in coil is blocked, and only the hold coil is energized, to thereby enable a reduction in power consumption.
In the device disclosed in Japanese Patent No. 4214401, the pinion is pushed even during the driving of the starter motor (clunking), and hence electric power is wasted for the pushing operation of the pinion, which results in the deterioration of the fuel efficiency of the vehicle.
Further, in the pinion pushing control implemented in Japanese Patent No. 4214401, the pushing operation of the pinion is implemented with a maximum duty even after the pinion engagement, and hence electric power is wasted for the pushing operation of the pinion, which results in the deterioration of the fuel efficiency of the vehicle.
Further, in the device disclosed in Japanese Patent Application Laid-open No. 2002-122059, a constant current is always supplied to the hold coil during the driving of the starter motor, and hence the amount of reduction in power consumption is small, with the result that an effect of improving the fuel efficiency of the vehicle is small.